The present invention relates to a conveying device for persons with directly driven step bodies which run forward in one direction one after the other and run back substantially thereunder. A conveying device for personsxe2x80x9d is to be understood to include a moving walkway or an escalator, and that xe2x80x9cstep bodiesxe2x80x9d includes plates or steps as appropriate.
Such a conveying device for persons is known, for example, in the form of a moving walkway from DE 19837915 A1. The plates are driven by means of a linear drive. For this purpose, they have permanent magnets which co-operate in a known manner with coils arranged thereunder. So that the position of the plates relative to one another is maintained, a chain to which the plates are fastened is, as in the case of conventional moving walkways, provided. In this known moving walkway the chain serves, however, only for guidance, the motive forces for the drive being primarily exerted by the linear drive. By virtue of the direct drive, wear of the chain is, in fact, lessened, but nevertheless still present, which has the consequence of requiring corresponding maintenance operations. A further disadvantage is that the position of the plates relative to one another must always be the same so that the plates directly adjoin one another even in the return run.
It is the object of the present invention to eliminate these disadvantages and to create a conveying device, and a step plate for such a device, with reduced maintenance outlay, for persons.
According to the invention this object is met by a conveying device for persons of the aforementioned general type, wherein the conveying device for persons is chain-free, that each step body runs on rollers and is driven by at least one electric motor. Each step body has a device for current supply and at least one sensor for determining the spacing from an adjacent step body, wherein a control electronic system is provided which controls the electric motor or motors in dependence on the signal of the sensor or the sensors. A respective tipping station for inclining the step bodies is provided at each of the ends of the conveying device.
According to the present invention several step bodies, preferably at regular spacings, or, alternatively each step body, have or has its own drive. A central drive is no longer present, and the otherwise usual chain, which connects all step bodies together into a step body belt, i.e. into a plate belt or a step belt, is also absent. Each step body can therefore be individually exchanged if maintenance should be necessary. This shortens replacement time, so that the conveying device has to be taken out of operation only very briefly. The step bodies do not need to be turned over at the ends of the conveying device so that the step bodies can also run back. Tipping stations are therefore present where the step bodies are inclined so that they pass from one path to another path. The installed drive is thus available even for return running. A further advantage results from the fact that in the case of conveying devices for persons, which are exposed to rain, no water can collect in the underside of the step bodies during the return run.
A particular advantage of the present invention consists in that the step bodies can be allowed to run back more quickly than they run forward. Thus, fewer step bodies are required for the conveying device for persons than previously needed.
Each step body may be connected to a current supply rail by way of wipers. The current supply rail may have a copper track, and the wiper a spring-loaded electrical carbon brush. A reliable current supply of the step body is thereby ensured.
In a preferred development of the invention, in the case of a moving walkway, the guide tracks and the necessary shafts may be provided at the building side. Only the self-propelled plates and the current supply devices remain to be installed. Large free lengths of the moving walkway support frame which depend on the construction and the guide tracks thereof are avoided and the costs of such moving walkways or escalators are thereby reduced. Since there is no cantilevered support and guide tracks to be set into oscillation by the plates travelling therealong, a moving walkway of the present invention is distinguished by a high degree of quiet running.
The present invention also comprises a step body for a conveying device for persons, which is characterised by the fact that it runs on rollers, of which at least one is driven by an electric motor. The step body has means for current supply and at least one sensor for determining the spacing from another step body, wherein a control electronic system is provided which controls the electric motor or the electric motors in dependence on the signal of the sensor or the sensors.
Preferably, two rollers are driven by two mutually independent electric motors. In this manner the step bodies are largely secure against breakdown, because they can also be driven, if necessary, by one of the electric motors. It is also advantageous if four sensors are mounted at the four corners of the step body. Thus, the spacing can be ascertained not only from the step body in front, but also from the step body behind, and also slight angled deviations between the step bodies relative to the travel direction can be recognised.
A drive which provides particularly true tracking is achieved if the electric motor drives front and rear rollers. In that case, the rollers can, particularly in the case of use for an escalator, be constructed as gearwheels which engage in racks, or corresponding appropriate profile members, fixedly arranged along the travel path. Such a mechanically positive or force-locking drive makes it possible to transport large conveyed loads, in a given case over large inclinations, and to dimension the conveying path to be as short as possible in the case of bridging over a predetermined height difference.
According to a further preferred embodiment the guide rollers of the step body may run as non-driven rollers along the guide tracks, while the drive of the step body takes place by way of a so-called friction wheel drive. The electric motor mounted to the step body in that drives a friction wheel, which is pressed by means of spring force against a stationary drive rail mounted along the travel path, and moves the step body while it rolls along the drive rail.
The current rail and the guide rail may be physically connected together in such an embodiment. This simplifies mounting and ensures a reliable current supply of the electric motor.